Sheet controlled interrupter for offset printing presses



1951 c. w. HARRO .D ET AL 2,578,700

SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES Filed July 12,1946 6 Sheets-Sheet 1 INVENTOR: CAMP/.55 VIZ/702201.12 BY flew/w? 5.Waooew-w Dec. 18, 1951 c. w. HARROLD ET AL SHEET CONTROLLED INTERRUPTERFOR OFFSET PRINTING PRESSES 6 Sheets-Sheet 2 Filed July 12, 1946 F1610INVENTORS CHARLES W l/nnemo By 1 27710? 5. Wow/PUFF T'TOIQNEYS Dec. 18,1951 c. w. HARROLD ET AL 2,578,700

SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES 6 Sheets-Sheet5 Filed July 12, 1946 T. 0 R w Wm nW r I n r W5 A 1951 c. w. HARROLD ETAL 2,578,700

SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES Filed July 12,1946 6 Sheets-Sheet 4 IN VEN TORS O/muss w/mmeobo ien/0e 5. WOOORUFF 2 2W Z W, I i HfTOE/VE Y5 Dec. 18, 1951 c. w. HARROLD ETAL SHEET CONTROLLEDINTERRUPTER FOR OFFSET PRINTING PRESSES Filed July 12, 1946 6Sheets-Sheet 5 INVENTORS C/IABL'ES Wl/nezou: y flan/0e 5. WOODEUFF Dec.18, 1951 c. w. HARROLD ET AL SHEET CONTROLLED INTERRUPTER FOR OFFSETPRINTING PRESSES Filed July 12, 1946 6 Sheets-Sheet 6 INVENTOR5611142455 Wf/Aw y flew/0e 5. M/ooaeuFF Patented Dec. 18, 1951 SHEETCONTROLLED INTERRUPTEB FOR OFFSET PRINTING PRESSES Charles W. Han-old,University Heights, and

Arthur B. Woodrufl, Brecksville, Ohio, assignors to Harris-SeyboidCompany, Cleveland, Ohio, a corporation of Delaware Application July 12,1946, Serial No. 683,130

16 Claims.

This invention relates to improvements in printing presses, and has todo particularly with impression throwofi mechanism for-rotary ofl'setpresses, especially mechanism for throwing the blanket cylinder off fromthe plate cylinder and from the impression cylinder in two sequentialsteps, and to means responsive to failure of sheet feed for setting suchmechanism into operation.

One of the objects of the invention is the provision of means dependentupon the presence or absence of a sheet in the printing unit itself forcontrolling the throwoff for that unit, so that if action of the feederserving the press is interrupted the desired throwofi of the press unittakes place at the desired time regardless of the extent of sheettransfer means employed between the sheet feeder and the impressioncylinder.

Another object is the provision of improved inner and outer eccentricmountings for the blanket cylinder.

Another object is the provision of improved means for adjusting theimpression pressure or compensating for different stock thicknesses as apart of the throwofi mechanism.

A further object is the provision of throwofl means comprising twotoggle mechanisms in series for enabling the throwoii to functionproperly in spite of adjustments of the anchor pivot of the togglemechanism directly connected with the eccentric mounting of a cylinder.

Still another object is the provision of sheet detector means acting tolatch the throwofl mechanism in printing position except when a sheetfails to be presented properly to the sheet grippers, and servingelectrically in such case to withdraw the latch at a given point in thecycle of the unit.

Another object is the provision of means for disabling partially orcompletely the throwofi mechanism when desired.

Other objects and features of novelty will appear as we proceed with thedescription of that embodiment of the invention which, for the purposesof the present application, we have illustrated in the accompanyingdrawings, in which Fig. 1 is a diagrammatic side elevational view of oneprinting unit of a rotary offset press embodying the invention, andshowing the impression on.

Fig. 2 is a continuation of Fig. 1 showing a portion of a sheet feeder,and sheet transfer mechanism interposed between the feeder and the firstunit of the press.

Fig. 3 is a view similar to Fig. 1 but showing both parts of thethrowofi mechanism operated to provide a narrow gap between the blanketcylinder and each of the other cylinders of the unit.

Fig. 4 is a view similar to Fig. 3 but with the second part of thethrowofl mechanism disabled, operating contact between the plate andblanket cylinders being accordingly maintained.

Fig. 5 is a. detail sectional view on a larger scale showing a sheetgripper and accompanying sheet feeler with electrical contactscontrolled thereby, the view being taken substantially on the line 5-5of Fig. 6.

Fig. 6 is a fragmental view at right' angles to Fig. 5.

Fig. 7 is a detail view on a larger scale of the eccentric means foradjusting the position of the anchor pivot for the toggle mechanismwhich operates the throwofl. of the blanket cylinder from the impressioncylinder, the view being taken substantially on the line 1-1 of Fig. 8.

Fig. 8 is a plan view, partly in section along the line 8-8 of Fig. '7.

Fig. 9 is a detail elevational view on a larger scale looking in thedirection of arrows 9-8 of Fig. 1.

Fig. 10 is a sectional view through one end of the blanket cylindermounting, the view being taken substantially on the line I0l0 of Fig. l,and

Fig. 11 is an enlarged view oi a portion of a feeder throwoff shown inFig. 2.

In the drawings I0 is the impression cylinder of a rotary offsetprinting unit, which also comprises a blanket cylinder H and a platecylinder l2. A blanket I3 is wrapped around cylinder II and securedwithin the gap 14 thereof in the usual manner, and the usual plate l5surrounds cylinder l2 and is clamped within gap it of that cylinder.

Plate cylinder shaft I1 and impression cylinder shaft it are carried inthe main frame I! of the press, these shafts being preferably mounted infixed journals in the frame. The cylinders are rotated in the directionsshown continuously during the operation of the press by gearing ofconventional character, not shown.

The impression cylinder I0 is equipped with the usual gripper shaft 20carrying a series of sheet grippers, a particular one of which is'shownat 2|. These grippers may be secured directly to the gripper shaft as bysetscrews 22, or they may be loosely mounted upon the gripper shaft andactuated in a well-known manner by dogs keyed to the shaft. In eitherevent they Y are opened and closed at the proper times by any suitablemechanism, not shown.

Sheets may be conveyed to grippers 2| by any "shaft 45.

suitable means. In the illustrated case this means comprise a conveyingcylinder 23 provided with grippers 24 which function to release a. sheetas it is taken by grippers 2 I. The sheets are car ried by the lattergrippers and by the impression cylinder |9 into contact with blanketcylinder by which they are printed, and thence to the grippers 25 of adelivery cylinder or any other suitable device for conveying sheets to adelivery or to another unit of the press.

The blanket cylinder H is provided with a shaft 26 rigid with thecylinder, each end of the shaft being supported in a bearing carried byan inner eccentric block 28 having a projecting ear 29 connected tomechanism for movement of the block through a small angle, as will bepresently described. Block 28 in turn is carried in an antifrictionbearing 3| within an outer eccentric block 32. Finally block 32 ismounted within an antifriction bearing 33 carried in the main frame i9.Eccentric block 32 is provided with an ear 34 to which there isconnected mechanism, presently to be described, for turning block 32through a small angle.

Both ends of shaft 26 are mounted as above described, there being a pairof eccentric blocks 28 and a pair of eccentric blocks 32, each mountedin antifriction bearings. In conformity with common practice theseblocks will be referred to hereinafter simply as eccentrics.

A limited rotation of the two eccentrics 28 causes movement of thecylinder toward or away from plate cylinder |2 without substantiallyaltering its position in relation to impression cylinder l0, and alimited rotation of the two eccentrics 32 causes movement of the blanketcylinder toward or away from impression cylinder ||l withoutsubstantially altering its relation to plate cylinder i2. The center ofshaft 28 is indicated at a, the center of eccentric 28 at b, and thecenter of eccentric 32 at c.

At each side of the press ear 34 of eccentric 32 carries a pin 35 whichis connected by a link 36 of adjustable length to a pin 31 of a lever 38keyed to a shaft 39 which extends across the press, shaft 39 beingsometimes referred to hereinafter as an anchor pivot. Shaft 39 isrotatably mounted near each end in a link 40 which is pivotallysupported on a stud 4| in frame l9, see particularly Fig. 3. pin 42which takes into a hole in one end of a further link 43. The other endof the latter link is mounted on an eccentric bearing 44, keyed to ashaft 45, the latter shaft being rotatably journaled in frame i9 andextending across the press.

At one side of the press, just inside the main frame IS, a worm wheelsector 46 is keyed to This sector meshes with a worm 41 keyed or pinnedto a short shaft 48 between bearings 49 fixed to the inner surface offrame l9. Shaft 48 is rotatable in bearings 49 and in a hole in a stud50 fixed in frame l9, and has secured to its upper end a knob which maybe turned by hand.

Through the connections just described it is possible, by turning knob5|, to adjust the angular position of shaft 45 and thereby move theshaft 39 bodily toward or away from the center of shaft 45, the shaft 39moving at all times parallel to itself in an arc about the studs 4|.This adjustment of shaft 39 enables the operator to limit the extent ofmovement of blanket cylinder toward impression cylinder l9 when thelever 38 and link 36 are in posi- Each link 40 carries a tion to bringshaft 39, pin 31 and pin 35 substantially into alignment as shown inFig. l, in other words when the toggle composed of lever 38 and link 36is on toggle." In practice the position of the blanket cylinder withrespect to the impression cylinder for different impression pressures orfor different stock thicknesses is indicated by graduations upon asuitable scale carried by the frame, the pointer for such scale beingcarried by the shaft or the sector 46.

Each of the levers 38 is provided with a second pin 52 which rotatablyreceives one end of a link 53, the other end of which surrounds a pin 54in a lever 55 which is carried on a shaft 56 Journalled in frame I9.There are levers 55 on both ends of shaft 56. These levers are rotatablethrough a limited angle from a position where abutment 51 of each leverengages a stop screw 58 carried by frame H] as shown in Fig. 1 to aposition where shaft 56, pin 54 and pin 52 are in substantial alignment,as in Fig. 3. In practice pin 54 is moved slightly past the position ofalignment, whereby the parts tend to remain on toggle."

The lever 55 on one side of the press is provided with two outwardlyprojecting studs, 58, 60, on opposite sides of shaft 56. These studs areadapted to be engaged selectively by a thrust block 6| having shoulders62, 63 for engaging the studs 59, 68, and an upward projection 64 forlimiting the sidewise movement of block 6|. Block 6| is pivotallymounted on pin 65 in bell crank 66' rotatably supported on stud 61 inframe IS. The other arm of hell crank 66 is connected by link 68 to oneend of a cam lever 69 pivoted on stud 69 the other end of which levercarries a follower 10 which follows a cam 7| keyed to shaft 12 ofdelivery cylinder 25. Lever 69 is urged toward cam H by spring 13.

By means of the mechanism described, cam H causes thrust block 6| to beperiodically raised and lowered to engage one or the other of the studs59, depending upon whether block 6| is moved to the left or right on itspivot 65. The means employed to control the position of block willbedescribed hereinafter. If this block engages pin 66, lever 55 isturned counterclockwise to the position shown in Fig. 1, thereby pullinglever 38 down until shaft 39, pin 31 and pin 35 are substantially inline, that is on toggle. This causes rotation of eccentrics 32 and movesblanket cylinder toward impression cylinder in. If block 6| engages pin59, lever 55 is swung clockwise until shaft 56, pin 54 and pin 52 aresubstantially in line, that is on toggle as in Fig. 2, and pin 31 ismoved off toggle." This causes eccentrics 32 to rotate clockwise andmove the blanket cylinder away from the impression cylinder.

The eccentrics 28 are moved by the following means. On each side of thepress a pin '14 is mounted in ear 29 and connected by rod 16 to a pin I6in a lever 11 similar in function and operation to lever 55. Levers Hare keyed to a shaft 18 extending across the press and have movementfrom a position against stop screws I9 such that shaft I8, pin 16 andpin 14 are substantially on toggle as in Fig. 1 to the position shown inFig.3.

A lever 11 on one side of the press only has two outwardly projectingstuds 80, 8| which are adapted to be engaged by the shoulders 82, 83 ofa thrust block 84 pivotally carried on stud 85 mounted in a cam lever 86which is pivoted on a stud 81 in frame I0. Lever 80 at one end has afollower 88 which is pressed against cam 1| by spring 89 acting on theother end of the lever. As cam 1| rotates it rocks lever 88 andraisesthrust block 04 into engagement with one or the other of the studs 80,8|. when it engages stud '80, lever 11 is turned clockwise to theposition of Fig. 1 where pin 10 is on toggle" and eccentric 28 has beenturned counterclockwise to move the blanket cylinder toward the platecylinder I2. when block 84 engages stud 8| lever 11 is turnedcounterclockwise to the position shown in Fig. 3 where pin 10 is "offtoggle and the blanket cylinder has been moved away from the platecylinder I2.

The two levers 11 and 55 are interconnected by the following means.Lever 11 carries a stud 90 which is connected by rod 9| to a noddle pin92 inlever 93, see Fig. 4, which is loosely mounted on a pivot stud 94in frame I0. On this same stud 94 there is also pivotally mounted a bellcrank lever 95, the lower arm of which carries a noddle pin 96 in whichslides a rod 81 having a head surrounding stud 98 fixed in thrust blockSurrounding rod 91 there are two compression springs 99, I00, onopposite sides of noddle pin 00 abutting against collars IOI and I02.

Lever 93 and bell crank 95 are arranged so that movement of the formeris transmitted to the latter or is not so transmitted, according to thedesire of the press operator. Lever 93 is provided with a hole I03, Fig.4, and bell crank 95 is provided with a slidable pin I04 which may beinserted into hole I08 when it is desired to lock the two leverstogether for movement in unisun, which pin may be retracted fromengagement with hole I03 when it is desired not to transmit movement oflever 93 to bell crank 95.

By the connections just described it will be seen that when pin I04 isin position in hole I03 a movement of lever 11 to the right to theposition shown in Fig. 1 will cause thrust block 6| to be resilientlypulled over against stud 60 of lever 55, and movement of lever 11 to theleft to the position shown in Fig. 3 will cause block 6| to beresiliently pushed over against stud 59. If pin I04 is withdrawn fromhole I03 as in Fig. 4, movement of lever 11 in either direction willhave no effect on block 6|, but due to the action of gravity upon bellcrank 95 projection 64 on block 6| will tend to rest against stud 59.

Thrust block 84 is swung to the right or left about its pivot inaccordance with the presence or absence of a sheet on impressioncylinder I0 by the following mechanism. A control rod 105 extends from astud I06 in block'84 through a noddle pin I01 in an arm I08 which ispivoted on a stud I09 in frame I9. Rod I05 is provided with two collarsH0 and III and a spring II2 to form a resilient connection in onedirection between rod I05 and noddle pin I01. A spring rod II3 connectedto arm I08 and passing through a hole in stud H4 in frame I9 carries aspring II5 which acts against collar II6 to urge arm I08 toward theright.

Arm I08 is provided with a lug II1 which abuts against an adjustablescrew 8 that is received in a threaded hole in a lever I I9 pivotallymounted on pin I20 in a bell crank I2I. limited movement about pin I20,as indicated in Fig. 9. The lever is held in normal operative position,that is with screw H8 in line with abutment II1, by means of a detentdevice I23 which engages an indentation in hell crank I2I. Lever H9 isalso movable to an inoperative position in which screw 8 is out of linewith abutment H1, in which position it is held by the detent device I23engaging another indentation in bell crank IZI.

The other arm of bell crank I2| carries a noddle pin I24 through whichextends one end of a rod I25 which is secured against movement in thenoddle pin by collars I26. The other end of rod I25 has a head whichsurrounds a stud I21 in a cam lever I28 having a follower I29 whichfollows cam 1|. Spring I30 surrounding rod I25 abuts against one of thecollars I26 and against a slotted stud |3| for urging follower I29against the cam.

The action of cam 1|, lever I20, and rod I25 is to move bell crank I2Iback and forth about its pivot I09 with each rotation of the cylinders,that is once during each cycle of the press. Owing to the pressure ofspring II5, arm I08 tends to follow the movements of hell crank |2I andmaintain abutment H1 in contact with screw II8.

Arm I08, however, is arranged to be latched at times in its left handposition, so as not to follow the movement of bell crank I 2| and forthis purpose is provided with a hardened plate I32 which is adapted toengage a notch I33 in a latch bar I34 pivoted to the frame at I35 andpressed downwardly by a spring I36. The free end of latch bar I34 isconnected by a link I31 to the armature I38 of a solenoid I39 secured tothe frame I9 by bolts I40. The coil'I4I of the solenoid is adapted to beenergized by electrical power, preferably of low voltage, supplied bylead wires I42, I43, from a suitable source, not shown. One of theleads, I42 as shown, is connected-directly to the coil I4I, while theother lead I43 is connected through switching mechanism now to bedescribed to the incoming lead I44 of coil MI.

The two wires I43; I44, pass through an opening I45 in frame I9 and areconnected to two metal brushes I46, I 41 which are held in a bracket I48secured by screws or the like to the inside surface of frame I9. Thesebrushes bear against the surface of a flat annular ring I50 which isfastened to the end ofcylinder I0 by means not shown. Ring I50 is formedof electrically nonconducting material; Inserted in the ring are twometal contact plates I5I, I52 which are adjacent each other but radiallyspaced so asto pass beneath and into contact with brushes I46, I41,respectively. These plates |,5|,- I52, are connected to wires I53, I54which lie in grooves formed in the inner face of ring I50, and, at apoint adjacent the gap in the periphery of the cylinder I0 pass throughan opening I55 in the end wall of the cylinder into the gap. As shown,particularly in Fig. 5, wire I54 is connected to contact point I56carried on a stud I51 which is secured on a Lever II 9 has when there isno sheet in the gripper 2|, spring I62 will urge arm I6| of the detectorfinger outwardly between the bifurcations of the gripper 2| until thecontact point I59 engages contact point I56. But when a sheet ispresented by grippers 24 and gripped by grippers 2| against 7 pad I 83the sheet will depress arm I" into the recess in pad I83 and causecontact points I58, I59 to separate.

The position of the metal plates II, I52 is preferably so chosen inrelation to the position of the gripper 2| and the location of brushesI48, I41, that the plates I5I, I52 will make contact with the brushesI48, I41 very shortly after the gripper 2| has closed upon the sheet,thereby giving ample time for the mechanism controlled thereby tofunction properly.

I18 represents the feed board of a pile feeder. Sheets are conveyed downthis board by tapes in the well-known manner of such feeders. Suitablemeans for throwing off the feeder action are employed to take effect incase arsheet fails to strike the front registering means on the feedboard at the proper time, or in case a sheet approaching the saidregistering means is crumpled, folded or askew. Figs. 2 and 11illustrate one means for this purpose.

Front registering means are illustrated at I89, and HI represents adetector finger approximately in transverse alignment with the saidregistering means. Preferably there are two such fingers spacedtransversely of the feed board. The fingers I1| are integral withforwardly projecting fingers I12, these two parts thus constituting abell crank lever which is pivoted at I13 upon an arm I14 that is pinnedto an oscillating shaft I15 and carries the said registering means I89.Gravity tends to move the bell crank counterclockwise on its pivot I13.A second oscillating shaft I18 carries a depending latch bar I11 and adepending leg I18 which is provided with a rearwardly projecting footI19 having a V-shaped extremity. I

A fixed stud I88 supports a bell crank lever having arms |8I and I82.Arm I8| carries a pad I83 which is adapted to engage the end of latchbar I11, while arm I82 has an articulated connection with alongitudinally movable rod I84 which is subjected to pressure by aspring I85 tending to move the rod forward but prevented by cam actionfrom doing so during the major part of each cycle of the feeder.

{when a properly fed sheet strikes a finger I" the corresponding fingerI12 is lifted to the position of Fig. 11, so that when the leg I18swings rearwardly its foot I19 moves beneath finger I12 and latch barI11 moves into position above pad I8 3 thereby preventing spring I85from forcing the, rod I84 forwardly. Arm I14 will then rise because ofthe oscillation of shaft I15, and the sheet will be fed forward bysuitable pull-out rollers or the like.

if on the other hand a sheet should fail to appreach the front stops atthe proper time in the cycle of the feeder, finger I12 through theaction of gravity will take a position lower than that illustrated, thatis until finger I1| bears against a stop I88. In this lower position theforward extremity of finger I12 will engage the V-notch in foot I19 asthe leg I18 swings rearwardly, and thus will hold latch bar I11 in thebroken line position, or clear of the pad I83. Accordingly, when thepreviously mentioned cam means permits, spring I85 will drive the rodI84 forwardly, which will function in any known manner to stop feederaction.

I98 represents a sheet transfer device having sheet grippers I9I, thisdevice being preferably a rotary device of irregular motion adapted totake a sheet from the feed board while the sheet is moving at less thanpress speed and accelerate it to press speed at the time of its transferto a second constant speed transfer cylinder 28. previously mentioned,which rotates at press speed and is provided with the grippers 24 whichare adapted to deliver the sheet to the grippers 2| of the impressioncylinder I8.

In the normal operation of the press, a sheet is presented at eachrevolution of cylinder 8 to the grippers of that cylinder and theclosing of gripper 2| on the sheet causes the sheet to move arm I8|inwardly, thereby separating contact I59 from contact I58 and keepingopen the circult to solenoid I38 at the time when plates I5l,

I52 pass under brushes I48, I41.

Under such conditions the armature I38 is free to remain in its downwardposition allowing latch bar I34 to be pressed down by spring I38 intoposition for its notch I33 to engage plate I32 of arm I88. Under theseconditions, bell crank I2I continues to oscillate back and forth at eachrevolution of the press under the influence of cam 1| acting upon leverI28 and rod I25 but it has no influence upon arm I88 other than torelieve the pressure of plate I32 against notch I33 each time the screw8 is brought into contact with lug II1 of arm I88 at the leftward end ofits stroke.

If, however, there is an interruption in the presentation of sheets toimpression cylinder I8, with the result that no sheet is present whengripper 2| closes on pad I83, arm I8| of the detector finger remains inits outward position and contact points I58, I59 remain closed. Shortlythereafter, the rotation of cylinder I8 brings plates I5I, I52 intocontact with brushes I48, I41 thereby completing the electrical circuitto solenoid I39 and causing armature I31 to be quickly lifted to theposition shown in Fig. 3. This occurs at the time when the pressure ofplate I32 on notch I33 has been relieved by cam 1|, as previouslydescribed, and causes the unlatching of arm I88 by latch bar I34. ArmI88 is thus free to be pressed by its spring II 5 toward the right andto follow the movement of bell crank I2I under the control of cam 1| ArmI88 in moving toward the right acts through rod I to pull thrust block84 to the right over against stud 8|. Thereafter on the next upwardmovement of block 84 stud 8| is raised by shoulder 83 and lever 11 isthereby swung to the left into the position shown in Fig. 3. Thecorresponding lever 11 on the opposite side of the press experiences asimilar movement since both levers 11 are keyed to shaft 18. Thismovement breaks the toggle between shaft 18 and eccentrics 28 and causesthese eccentrics to be rotated somewhat clockwise thereby moving blanketcylinder I I away from plate cylinder The movement of lever 11 towardthe left imparts a downward thrust to rod 9| which acts through lever 93and bell crank (assuming pin I84 is in its normal position in hole I83)and rod 91 to resiliently push thrust block 8| to the left against pin-59 so that, on the next upward movement of block IiI, pin 59 will belifted by shoulder 82 and lever 55 will be swung toward the right as inFig. 3. This movement of lever 55 imparts an upward thrust through rod53 to pin 52 until pin 54 reaches the on toggle position. The upwardthrust on pin 52 turns lever 38, and consequently also shaft 39 therebybreaking the toggles on both sides of the press between shaft 39 andeccentrics 32 and giving these eccentrics a slight clockwise rotation tomove ments just described, and a sheet isthen pre-,

sented to grippers 2| the mechanism functions to throw the impressionon" in the same sequence, that is, the blanket cylinder II moves towardplate cylinder I2 first and toward impression cylinder I second in thesame cycle, these movements occurring during passage of the gaps pastthe lines of centers of their respective cylinders.

When the inner eccentric is operated to throw the blanket cylindertoward the plate cylinder it exerts a wedging action upon the outereccentric which tends to resist movement of the latter eccentric. Hencethe operation of the outer eccentric to shift the blanket cylindertoward the impression cylinder is opposed by this wedging action.However, because of the antifriction hearings on both'sides of the outereccentric, it is possible to effect the required movement of the latterin spite of the additional load imposed upon it by this wedging action.

Thus, starting with the parts in off position and with impressioncylinder I0 approaching the sheet receiving position, the high spot ofcam II travels under follower I29, as in Fig. 1, causing bell crank I2Ito move arm I08 to the left into latching position. Gripping of thesheet by gripper 2| opens contact points I58, I59 thereby keeping thecircuit to solenoid I39 open during the time plates I5I, I52 contactbrushes I46, I41. Latch bar I34 thus is permitted to remain in its lowerposition to latch up the arm I08 so that as follower I29 rides down camII arm I08 will not be permitted to follow bell crank I2I toward the riht.

'I'he leftward movement of arm I08 puts block 84 over against pin 80 sothat as the high point of cam 1| comes under follower 88 block 84 pushespin 80 up and rocks lever 11 into the on toggle" position thereby movingeccentrics 28 counterclockwise and moving cylinder II toward platecylinder I2.

The rocking of lever 11 to the right raises rod M and thereby movesblock 8| to the right against pin 80 so that when the high point of camII passes under follower I0 block 8| pushes pin 80 upward and moveslever 55 to the left thereby pulling levers 38 down into the on toggleposition and moving eccentrics 32 counterclockwise to move cylinder IItoward impression cylinder I0.

When it is the desire of the operator to run the press without sheetsand with the blanket and plate cylinders in contact, as for rolling up,the blanket in preparation for printing, he first cuts off the electricpower to the solenoid I39, as by opening the line switch I99 (Fig. 1),so that the latch bar will not be raised and lever I08 will remain inthe latched up position, then he removes pin I04 from hole I03 in lever93 and moves, or permits gravity to move, bell crank 95 down so thatlink GI bears against stud 58. Under these conditions, as shown in Fig.4, the pressure between plate and blanket cylinders remains on while thepressure between blanket and impression cylinders remains off.

"In case it is the desire of the operator to run sheets through thepress without pressure of the blanket cylinder against either of theother two cylinders, as when testing sheet feeding and I handling, hemerely swings lever II9 about pin I20 to the position in which screw H8is out of alignment with lug I I! so that movement of lever II9 willhave no influence on lever I08, then he lifts latch bar I34 to allowlever I08 to move to the right under the pressure of spring II5 thus.shifting link 84 over against pin 8|. This puts eccentrics 28 in theoff position on the next revolution of cam II. If pin I04 is in itsnormal position in hole I03 the movement of lever 11 will set link 6| tothrow off the eccentrics 32. If pin I04 is not in hole I03, link 6| willbe set in the latter position automatically by action of gravity aspreviously mentioned. Under the conditions just described, pressurebetween all cylinders will remain off regardless of the presence orabsence of a sheet in gripper 2I.

When the operator desires to adjust the blanket cylinder toward or awayfrom the impression cylinder I0 in order to accommodate sheets ofdifferent thickness or for changing the amount of printing pressure, heturns knob 5| in the proper direction to move shaft 39 toward the rightabout its pivot M for setting the blanket cylinder closer to theimpression cylinder and toward the left for the reverse effect.

The mechanism illustrated in Figs. 2 and 11 serves to stop the operationof the feeder in the event that a sheet fails to strike the detectorfinger III at the proper time in the feeder cycle. This actionconventionally serves to set in motion means for throwing off theimpression of the printing press when the sheet last fed has beenprinted. This of course calls for delayed action mechanism, and wherethe sheets before being presented to the first impression cylinder mustpass over intermediate transferring elements such as the cylinders I and23 of the illustrated case. such mechanism must be somewhat complex. Inaccordance with the present invention, however. the impression throwoffis not directly afiected by the feeder throwoff. but is set in operationat the proper time by the failure of the feeder to present a. sheet tothe first printing unit.

Having thus described our invention, we claim:

1. In a machine f the character described, a feed table for supportingsheets fed automatically in timed sequence, front registering meansassociated with said table, a printing press having an impressioncylinder, sheet grippers thereon adapted to take sheets advancing fromsaid feed table, impression throw-off mechanism, sheet detecting meansassociated with said front registering means, means set in motion bysaid detecting means for stopping the feed of sheets in the absence of asheet at said front registering means at the beginning of a press cycle,sheet advancing means-forward of said feed table timed to present tosaid impression cylinder grippers a sheet which has passed saiddetecting means and is in transit between said feed table and saidimpression cylinder, and means associated with the grippers on saidimpression cylinder, functioning in the absence of a sheet fed to saidcylinder, for setting said throw-ofi mechanism in impression offposition and holding it in that position until the next sheet is fed.

2. In a machine of the character described, a feed table for supportingsheets fed automatically tion with said impression cylinder, saidadvancing means being timed to present to said impression cylindergrippers a sheet the rear edge of which has passed said frontregistering means and is in transit between said feed table and saidimpression cylinder, impression throw-ofl mechanism, sheet detectingmeans associated with said front registering means operable to stop thefeed of sheets, and means associated with the grippers on saidimpression cylinder, functioning in the absence of a sheet fed to saidcylinder, for setting said throw-oil mechanism into operation.

3. In a machine of the character described, a feed table for supportingsheets fed automatically in timed sequence, front registering meansassociated with said table, a printing press having an impressioncylinder, sheet grippers thereon, sheet advancing means forward of saidtable comprising a plurality of sheet transfer devices timed to presentto said impression cylinder grippers a sheet the rear edge of which haspassed said front registering means and is in transit between said feedtable and said impression cylinder, impression throwofl mechanism, sheetdetecting means associated with said front registering means operable tostop the feed of sheets, and means associated with the grippers on saidimpression cylinder, functioning in the absence of a sheet fed to saidcylinder, for setting said throw-off mechanism into operation.

4. In mechanism of the character described, a

frame, plate, blanket and impression cylinders, a pair of outereccentrics, roller bearings for said outereccentrics mounted in saidframe, a pair of inner eccentrics carried by said outer eccentrics, theshaft for said blanket cylinder being mounted in said inner eccentrics,impression throwofl means functioning to turn one pair of saideccentrics to separate the blanket cylinder from the plate cylinder, andimpression throwoff means set in operation by the actuation of saidfirst named throwoif means for separating the blanket cylinder from theimpression cylinder in the same cycle of the press.

5. In mechanism of the character described, a frame, plate, blanketandimpression cylinders, a pair of outer eccentrics, roller bearings forsaid outer eccentrics mounted in said frame, a' pair of innereccentrics, roller bearings for said inner eccentrics carried by saidouter eccentrics, the shaft of said blanket cylinder being mounted insaid inner eccentrics, and impression throwoff means functioning to turnsaid pairs of eccentrics in sequence, said means comprising means forturning the second pair of eccentrics set in motion by the means forturning the first pair.

6. In mechanism of the character described, a frame, plate, blanket andimpression cylinders, a pair of outer eccentrics, roller bearings forsaid outer eccentrics mounted in said frame, a pair of inner eccentricscarried by said outer eccentrics, the shaft for said blanket cylinderbeing mounted in said inner eccentrics, cam actuated means for turningsaid inner eccentrics first and said outer eccentrics thereafter insequence during a press cycle to throw off the blanket cylinder from theplate cylinder first and from the impression cylinder second, and meanssettable in advance to disable said means for turning said innereccentrics, whereby the blanket cylinder will remain in conl2 tact withthe plate cylinder but will be thrown off from the impression cylinder.

7. In mechanism of the ,character described, a frame, plate, blanket andimpression cylinders, a pair of outer eccentrics, roller bearings forsaid outer eccentrics mounted in said frame, a pair of inner eccentricscarried by said outer eccentrics, the shaft for said blanket cylinderbeing mounted in said inner eccentrics, impression throwofl meansfunctioning to turn said inner eccentrics to throw said blanket cylindertoward said plate cylinder, and impression throwoif means set inoperation during the same cycle by said first named throwofi means forturning said outer eccentrics in their roller bearings to throw saidblanket cylinder toward said impression cylinder.

8. In mechanism of the character described, a frame, plate, blanket andimpression cylinders, a pair of outer eccentrics mounted in said frame,a pair of inner eccentrics carried by said outer eccentrics, the shaftfor said blanket cylinder being mounted in said inner eccentrics,impression throwofi means functioning to turn first said inner and thensaid outer eccentrics for moving said blanketcylinder relative to saidplate and impression cylinders in sequence in the same press cycle, saidsecond throwoff means functioning in response to the action of saidfirst throwoif means, and means interconnecting the eccen-. trics of oneof said pairs and operable at a single operating station to adjust theangular position of the latter eccentrics.

9. In throw-off mechanism for a printing press, an adjustable mountingfor the shaft of a cylinder, a toggle lever one end of which isconnected with said adjustable mounting, an anchor pivot for theopposite end of said lever, an arm pivoted at one end, a movablemounting for said anchor pivot at the opposite end of said arm, meansfor shifting the intermediate pivot of said toggle lever to on toggle oroff toggle" position, a link to one end of which said movable mountingis connected, an eccentric bearing for the opposite end of said link,and means for turning said eccentric bearing to adjust the position ofsaid movable mounting.

10. In throw-off mechanism for a printing press, an adjustable mountingfor the shaft of a cylinder, a toggle lever one end of which isconnected with said adjustable mounting, an anchor pivot for theopposite end of said lever, an arm pivoted at one end, a movablemounting for said anchor pivot at the opposite end of said arm, meansfor shifting the intermediate pivot of said lever to on toggle," or "ofitoggle position, a link to one end of which said movable mounting isconnected, an eccentric bearing for the opposite end of said link, andnon-reversible means for turning said eccentric bearing to adjust theposition of said movable mounting.

11. In throw-off mechanism for an offset printing press, a pair of outereccentrics, a pair of inner eccentrics carried by said outer eccentrics,

a blanket cylinder journaled in said inner eccentrics mechanism forthrowing off the blanket cylinder from the plate cylinder, separatemechanism for throwing off the blanket cylinder from the impressioncylinder, means adapted to be actuated by the throw-off from said platecylinder for setting in operation the throw-off from said impressioncylinder, said means comprising twin elements one of which is adapted tobe driven and the other of which is adapted to drive, and detachablemeans for connecting said twin elements together, whereby the removal ofsaid asvsnoo detachable means disables said throwoff mechanism.

12. In throw-oi! mechanism m printing presses, a toggle lever arrangedwhen thrown to "toggle on position to move a cylinder to on position andmaintain it there, an adjustable anchor pivot for said toggle, a. secondtoggle operatively connected to said first toggle for moving said firsttoggle from one position to the other, a fixed anchor pivot for saidsecond toggle, and a swingable thrust block for operating said secondtoggle in either direction.

13. In throw-off mechanism for printing presses, a toggle lever arrangedwhen thrown to toggle on position to move a cylinder to on position andmaintain it there, and adjustable anchor pivot for said toggle, a secondtoggle operatively connected with said first toggle for shifting thefirst toggle to "toggle on" position when the second toggle is moved to-"toggle ofi" position and vice versa, a fixed anchor pivot for saidsecond toggle, and a swingable thrust block for operating said secondtoggle in either direction.

14. In throw-oil mechanism for printing presses, a printing couplecomprising a rotating cylinder, sheet grippers thereon, a feeler on saidcylinder adapted to be shifted by a sheet when gripped by said grippers,an electric circuit opened by said feeler when shifted, a secondcylinder, means for moving said second cylinder to on or off positioncomprising a toggle lever, a swingable thrust block for causing saidtoggle to assume either "toggle on or toggle ofl" position, a throw-oilcontrol for swinging said thrust block from one position to the other, alatch adapted to hold said control and said thrust block in position tomaintain said toggle in impression on position, magnetic meansresponsive to cur-- rent in said circuit for disabling said latch, andmeans for moving said unlatched control to swing said thrust block toposition for causing said toggle lever to assume impression offposition,

and cam means operable to return said throwofl gaged by roller bearings,and means for turning one of said pairs of eccentrics to press saidblanket cylinder against said plate cylinder and tor thereafter whilepressure is maintained 14 against said plate cylinder turning the otherpair of eccentrics to press said blanket cylinder against saidimpression cylinder.

16. A printing unit adapted for use in a multi unit press, said unitembodying a plate cylinder, a blanket cylinder and an impressioncylinder, said blanket cylinder being disposed between said plate andimpression cylinders with its axis to one side of the plane through theaxes of the plate and impression cylinders, impression throwoffmechanism effective to move said blanket cylinder out of contact withsaid plate and im pression cylinders in sequence, means compris ing a.feeler on said impression cylinder functioning in the absence of a sheetfed to said cylinder for setting said throwofi mechanism to move saidblanket cylinder out of contact with said plate cylinder and thereafterout of contact with said impression cylinder, said means finictioningalso to return said blanket cylinder ta impression on position relativeto said plate and impression cylinders in sequence during the cyclefollowing the taking of a correctly fed sheet by said grippers, cam andcam follower means timed to cause said sequentiai action to be completedin a fraction of one revolution of said impression cylinder, and meansfor placing each sheet on the impression cylinder more than saidfraction of revolution ahead of the printing line, and transfer meansfor taking sheets from said impression cylinder and advancing them tothe next unit of the press.

CHARLES W. HARROLD. ARTHUR B. WOODRU'FF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,193,045 Niles Aug. 1, 19161,327,182 Upham Jan. 6, 1920 1,351,175 Lehr Aug. 31, 1920 1,374,137Blaine Apr. 5, 1921 2,003,798 Barber June 4, 1935 2,018,282 RobinsonOct. 22, 1935 2,100,852 Jacobson Nov. 30, 1937 2,146,963 Lang Feb. 14,1939 2,356,058 Hunting Aug. 15, 1944 2,356,315 Gudger Aug. 22, 19442,419,403 Horton et al Apr. 22, 1947 FOREIGN PATENTS Number Country Date224,843 Great Britain Nov. 20, 1924 500,600 Great Britain Feb. 13, 1930

